Control system for sorting machine



July 5, 1965 Filed March .3,

R. L SWARTZ SYSTEM FOR SORTING MACHINE CONTROL C301 c/oses 2 Sheets-Sheet 1 July 5, 1966 Filed March l, 1964 R. L SWARTZ CONTROL SYSTEM FOR SORTING MACHINE Mm, hm

2 Sheets-Sheet 2 INVENTOR iC/ ard l.. Swarz ATTORNEYS 3,259,238 CONTROL SYSTEM FOR SORTING MACHINE Richard L. Swartz, Columbia, S.C., assigner to Universal Business Machines, Inc., Columbia, S.C., a corporation of South Carolina Filed Mar. 3, 1964, Ser. No. 349,031 6 Claims. (Cl. 209-72) This invention is concerned with a system for controlling the oper-ation of machines designed to sort articles and direct them along a trackway for storage into a number of different bins, examples being mail-sorting machines and other machines of this type commonly referred to as document-sorting machines.

One example of the type of document-sorting machine in question is disclosed in the U.S. patent to Benson No. 2,707,569 in which the articles to be sorted are fed in succession into the receiving end of -a guideway which is provided with a series of tiltable gates formed in the bottom of the guideway at different points along its length, so that when a gate is tilted upwardly out yof its normal plane, it will deect an article downwardly into a storage bin. Examples of suitable gate structures are shown in the U.S. patent to Rives No. 2,823,031 and in copending U.S. application Serial No. 109,427, filed May 11, 1961, now Patent No. 3,128,093.

The sorting operation in the Benson machine involves the selective control of different gates to efect delivery of the successive articles to the appropriate storage bins. The gates are selectively operated by suit-able electric circuits controlled from individual keys in a keyboard of the type used on typewriters. In this type of control the rate of sorting is limited by reason of the fact that only one article can be traveling along the trackway at any given moment, and -a second article cannot be released for movement along the trackway until the irst article has been deposited in its proper bin.

An object of the present invention is to devise a lcontrol system for selectively controlling the gates of a sorting machine in such manner that it is possible to have more than one article proceeding along the trackway at one time, and thereby increasing the sorting capacity of the machine. For example, in the embodiment described herein the number of articles sorted per hour is about 12,500, which is double the rate without the use of the present invention. A still greater increase in sorting rate is possible, as will appear below.

This is accomplished in the present invention by etfecting operation of the gates in two different groups which occupy different linear sections of the trackway (a forward section and a rear section), and also by providing two signal storage devices for storing of the signals from alternate articles to be sorted, that is, as the articles are presented at the entrance to the trackway the signal for one article would be stored in one signal store, and the code signal for the next article would be stored in the other signal store, and in alternation for succeeding articles. Each signal store is designed to store code signals for any gate in the trackway, so that at any one time a signal store may have -a signal stored therein representing either a gate in group F (the gates in the forward section of the trackway) or it could be a signal representing a gate in group R (the gates in the rear section of the trackway). Further, the stored signals on the two signal stores are fed alternately in alternate feed cycles by suitable switching means to effect energization of appropriate gate solenoids for the group F gates in one cycle and for group R gates in the next cycle. By this arrangement a signal can be in the process of being stored in one signal store while the other signal store is operating to open a gate in the rear section yof the trackway.

lUnited States Patent() 3,250,238 Patented July 5, 1966 Each set of storage relays, or signal stores, retains the stored signal for an interval equal to two feed cycles. By this arrangement any stored signal representing a gate in the tirst section of gates becomes elective immediately (during .the feed cycle in which it was stored) to operate the gate in the rst feed cycle portion of the storage interval. If the stored signal represents a gate in the rear group of gates, the stored signal does not become effective until the next feed cycle when the set of storage relays will be connected to the R gate solenoids. Thus, the storage interval for each set of storage relays is two operating cycles long, and the two storage intervals overlap so that the last half of the storage interval of one store coincides with the first half of the storage interval of the other store, and vice versa. As a result, any selected gate in the first or F group of gates is operated in one feed cycle and any selected gate in the second or R group of gates is operated -in the next feed cycle, which action is repeated in succeeding cycles.

Another object of the invention is to devise a control circuit which is automatic in its operation to proceed from one feed cycle to another so long as there is a supply of articles to be sorted.

Still another object of the invention is to devise a control system for an article-sorting machine in which each article carries a multiple-digit `code which indicates the destination or bin for the article, the system including separate elements to sense or read the digits individually and to effect storage in individual stores of any digits that are sensed, and in which the individual stores control single-pole, double-throw switches in different ranks of a tree-switching system, the branches of which are connected to a plurality of gate solenoids, whereby diferent cornbinations of said multiple-digit code effect connection to different ones of said gate solenoids.

FIGURE 1 is a diagrammatic showing of the arrangement for sensing the code signal applied to each article, the control cams which control various operations of the sorter, including the one-revolution clutch which operates the cams, as well as the circuit arrangement by which the articles are picked up one at a time and fed into the conveying trackway;

FIGURE 2 is a circuit diagram showing the switching arrangement for alternately energizing the coils in the two groups of gate selecting relays (the two signal stores), and for alternately energizing and deenergizing the coils of the relays which connect the input and output connections of the storage relays in the incoming signal and to the gate solenoids, respectively;

FIGURE 3 is a circuit diagram showing two sets of tree-circuits containing switches controlled by the relays of FIGURE 2 for selectively energizing gate solenoids according to the signals stored in the two signal stores;

FIGURE 3A is a diagram giving the code for three different switches controlled by a single relay coil; and

FIGURE 4 is a diagram giving the timing relations between the various switch-operating cams C1 to C8 of FIGURE 1.

Article feeding arrangement While various arrangements are possible for picking up the articles one by one from a supply stack and feeding them into a conveying trackway, the embodiment described herein uses the pickup arrangement disclosed in my copending application Serial No. 109,459, tiled May ll, 1961, now Patent No. 3,201,114, involving the use of a suction pickup head or cup for picking up the face or top document from the stack and transferring it to the entrance end of the conveying ltrackway, the movement of the pickup head from pickup position to the discharge position being controlled by a vacuum cylinder,

and `the vertical movement of the head from its normal position to pickup position being controlled by a solenoid.

The arrangement for controlling the operation of the ypickup head is shown within a dotted rectangle PHC in FIGURE l, as modified for use in the present invent-ion. Various elements which are common to copending application Ser. No. 109,459, now Patent No. 3,201,114, are indicated in FIGURE l by the same reference numerals with prime marks applied thereto.

Operation of the feed arrangement for the present invention is controlled automatically by cam C1 mounted on cam shaft CS which is driven from a constantly driven shaft Sh through a one-revolution clutch ORC which, in turn, is controlled by a clutch coil CL to produce one revolution of the cam shaft CS for each energization of the coil CL.

Description of article feed Cycle The circuits for the automatic feeding of an article to the conveying trackway and the energization of clutch coil CL will be explained with reference to FIG. l.

When the vacuum control pickup cup is in a position to pick up an article to be sorted, the contacts of extend switch PR' are reversed from 4that shown in FIG. l, thus a circuit is completed through the normally open but now closed contacts of switch PR', through the pickup coil 9' and through the normally closed contacts of switch VS to the opposite side of the bus thus energizing the pickup solenoid 9. With coil 9' energized, the feed head moves downward towards the top article to be sorted and opens a circuit at the safety switch 29'. When the pickup head contacts the top article in the stack of articles to be sorted, vacuum is built up in the head system and the vacuum control switch VS changes its position opening the circuit to the solenoid 9' and closing the circuit to the feed valve solenoid 22.

With the deenergization of solenoid 9', the pickup head raises up to the feed position and changes the contacts of switch 29' back to the position shown in FIG. 1. This completes a circuit from the supply line 27' through switch 29' and through the clutch solenoid CL to the opposite supply line 28', thus energizing the cam clutch solenoid CL which causes the clutch ORC to engage and start rotation of the cam shaft CS, with the cam members mounted thereon.

The rotation of the cams will cause the switch 34 to be operated by cam C1 which in turn will complete a circuit from the switch 29' through the now closed contacts of switch 34' through the feed valve solenoid 22' down through the normally open but now closed contacts of switch VS' lto the common side of the bus, thus energizing the feed valve solenoid 22. Energization of the solenoid 22' causes the feed head to start feeding the article to the conveying trackway.

The initiation of feed movement by the operation of switch 34 will cause extend switch PR to reverse its contacts back to the position shown in FIGURE 1.

Reversal of the contacts of switch PR' to their normal shown position energize head valve solenoid 26' which cuts off the vacuum supply to the vacuum cup, which by this time has the article moving at full momentum. Coincidentally, with the article being delivered, cam C1 has rotated through its predetermined arc of revolution as shown in FIGURE 4 and thus switch 34" has opened, thus de-energizing solenoid 22.

At this time an aperture in the feed head stem will be exposed to atmospheric pressure, thus releasing the remaining vacuum in the head system to effect delivery of the letter. The feed head will return to the extended position for the next pickup operation and in so doing will reverse the contacts of switch VS' to that shown in FIG- URE 1. The extend switch PR will now be reversed from that shown in FIGURE l, thus de-energizing the head valve solenoid 26' and thus allowing the vacuum supply to be returned to the on position. Vacuum will be applied to the pickup head upon the next cycle of energization of pickup solenoid 9'.

Code signal pick-up In the preferred embodiment of my invention, artic-les to be sorted, such as letters, cards, packages and so on, are each marked with a multiple digit code marking which controls the location at which the article will be discharged from the trackway. The code markings are applied in a fixed location on each article, as in the five areas represented by the blocks 1, 2, 4, 8, and 16 on article LR FIGURE l where each of the blocks represent one of the binary numbers l, 2, 4, 8, and 16, it is understood that any combination of code numbers may be substituted for the numbers referred to here. The code blocks are shaded to either reflect or absorb light in that I prefer to use a phot-oelect-ric system to read out the code markings; however, I do not intend to limit myself in any way to a photoelectric system since other forms of codes and code readers such as magnetic codes and scanning devices can obviously be substituted for use with my article sorter. The five referred to numbers are used because the sum total of these numbers will provide a combination of thirty-one divisions. This number corresponds to the number of article receiving bins and their respective bin gates employed in my sorting machine. By using five code areas it is possible to mark the areas in 3l different code combinations, and each combination will control `the gates to deposit the article into a particular bin. For example, assume an article carries a code marking such that all code areas are blackened except 2 and 8, these areas will energize their respective photo-cel-ls which in turn will control appropriate switches to energize the gate solenoid for gate No. 21, this gate number being the sum of values 1, 4 and 16 assigned to the three blackened areas.

Referring to FIGURE 1, five photoelectric cells, PE1, PE2, PE4, PES, PE16, are provided to scan corresponding blocks of the code carried by the article to be sorted. Each photoelectric cell controls an amplifying relay, thus PE1 controls relay SR1, PE2 controls relay SR2, etc., and these amplifying relays energize switch coils S1, S2, S4, S8 and S16, respectively. These switch coils are energized from a common circuit which is completed through a scan switch C2a -which is controlled Iby cam C2 to .remain Iclosed for approximately 65 of cam rotation, as shown in FIG. 44. The switch coils VS1 Ito lS16 of FIG. 1 control normally-open contact pairs in FIG. 2 marked Sla, 52a, 84a, S8a and S16a each of which, in turn, con- -trols two sets Iof gate-selecting relays in FIG. 2 marked 1-A, 1B; G-A, Z-B; 4-A, 4-13, -8-A, 8-B and 16-A, 16B.

Signal .stores All of the gate-selecting relays in the .two groups are provided with self-holding circuits, so that when a relay Iis operated in any group, .that relay remains locked in operated position until the holding circuit is released by operation of one of the cams C7 or C8. Thus, the gateselecting relays in lgroup A constitute one signal store, and the gate-selecting relays in group `B constitute la second signal store.

The holding circuits for the ltwo groups of storage relays are shown in FIG. 2. For example, relays 1A-1 to 1A--6 are energized over a common circuit completed through `the upper contact of switch ARl'l-Z, and a holding circuit for these six relay coils is completed through a normally opened contact 1A6-2 which closes when relay 21A-6 operates, and this holdingl contact completes a holding circuit to the holding conductor HA. Likewise, the coils of the six .relays 1B-1 to 1B-6 are connected in parallel and are energized through the lower contacts of switch ARH-2, and ythe normally opened contacts 1B6-2 are closed upon operation of relay 1B6 to establish a holding circuit for these relays `to .the holding conductor HB.

ln a llike manner holding circuits for the A groups 2-A, 4-A, 8-A and 16-A are .completed -to the holding conductor HA 4through holding contacts 2A3-3, l4A2-2, 8A1-3 and 16A1-2. Also, holding circuits for .the B lgroups Z-B, 4-B, 843 and Ali-B are completed to the holding conductor HB through self-closing .holding contacts 2B'3-3, 4B2-2, lSBI-3 and 16B11-2.

The holding conductor HA is normally connected to one supply line through the normally closed contact CSa controlled by the cam C8, and the holding conductor HB is normally connected 4to the same supply line through the normally closed switch contacts C7a controlled by the cam C7. The cam `switch CSa is timed to `open the circuit to holding .conductor HA just before ythe tive input signal circuits are switched to control the A group of storage relays, and the swi-tch C7a is .timed lto open just before the ve signal circuits are switched to energize .the B group of storage relays.

It will -be noted that the rive input signal circuits are switched alternately from Ithe A stores to the B stores by ve .single-pole, doublethrow .switches A\R11-2, AR11-3, AR12-1, AR12-2 and AR12-3 which are controlled by the alternating relay coils AR11 and AR12, respectively, see .the coils inthe AR col-umn at the `top of FIG. 2. All of the -thirteen .alterna-ting relay coils AR-l .to AR-1'3 are energized in parallel from the negative supply line through tthe normally open contact lof cam switch C7n, and .these relays are held in yoperated condition through a self-closing holding contact AR13-1 connected .to :holding conductor HA. The AR relays are released from operated condition Vupon opening of the cam switch CSG so that the AR relays are energized for one complete feed cycle, and are deenergized through the next complete feed cycle.

Switch-controlling cams The control system involves a number of switch-controlling cams shown in `FIG. 1 and marked C1 to C8, respectively. Cams C1 to C6 are mounted ion a cam shaft CS ywhich is driven through one complete revolution upon each energization of clutch coil CL twhichcouples `the shaft CS with a constantly rotating shaft Sh, and cams C7 yand G8 are mounted on another section CSC: of the cam shaft which is driven at onehalf the speed of shaft CS through suitable .speed-reducing transmission indicated ,at SRT.

As shown in FIGURE 1, the cam C1 controls the feed switch 34 to eifect one cycle `of feed operation, and cam C2 controls switch C2a to energize .switch coils Sil to S-16 during the scan interval of the yfeed cycle, .according to the code markings applied in areas 1, 2, 4, I8 and y16 applied to article LR. Operation of the remaining cams will be described below.

Switching trees Each of the rel-ay coils .shown in the AR column, FIG. 2, controls three single-pole, double throw switches which are connected in Itwo tree arrangements illustra-ted in FIG. 3.

The contacts controlled by t-he A bank of storage relay coils in FIG. 2 are connected in one .tree system 'which for convenience may be referred to as an A tree, :while `the contacts controlled by the B group of storage relay coils are connected in a second tree system which may be designated as the B tree.

As shown in FIG. 3, the contacts of the storage relays which form the A tree are larrange-d in :five columns or ranks, the iirst column or rank including .one single-pole, double-throw .switch 16A11, and .the .second rank including tW-o switches SAI-1 and SAI-2, iwhile the third rank includes hour switches, 4A1-1, 4A1-2, 4A1-3 and 4A2-1. The fourth column or rank .in the A tree includes eight .switches controlled by the relay .coils in the 2A group of FIG. 2 and marked correspondingly in FIG. 3. The ifth rank of switches in the A tree of FIG. 3 includes 6 sixteen switches controlled by the 1A group of relay coils 'of FG. 2, and as marked in FIG. 3. y

The B .tree switching system of IFIG. `3 is formed in an identical manner with the A tree and with the same nulmber of switches in the different ranks as in the A tree, the contacts .of lthe B tree being appropriately marked Iin FIG. 3.

Each of the thrteen AR relay coils shown in FIG. 2 also controls .three single-pole, double-throw switches which are connected to the branch circuits lof .the two switch trees in the manner shown in FIG. i3, and each AR switch is connected to energize a Agate solenoid, there being thirty-one solenoids as shown in FIG. 3, and each solenoid being .connected lto operate a gate .controlling access to different bins, as will be ydescribed below.

As explained above, each of the storage relay coils of FIG. 2, and each of the alternating relay coils of FIG. 2, controls three signal-pole, double-throw switches, as shown in FIG. 3A. It is convenient to use commercially available relays in which the relay coil and all three switch units are assembled on a common base which is provided with connecting prongs as numbered 1 to 11 in FIG. 3A. This numbering has been incorporated in FIG. 3 so that the three separate relays can be identitied, and it is possible to check which side of each relay is normally closed.

For purpose of illustration, the various circuits which may be completed by the A :tree of switches may be traced as follows: Starting from the T1 bus and going to the contacts 16A1-1, the connections from these contacts branch out to the contacts SAI-1 and SAI-2. The connections from contacts 8A1-1 branch out into a pair of switch contacts 4A1-1 and 4A1-2, the connections from which in turn branch out into a further pair of contacts, e.g., 4A1-1 branches into 2A1-1 and 2A1-2 and 4A1-2 branches into 2A1-3 and 2A2-1, and in a like manner, each of the 2A contacts branches out into a pair of contacts in the fifth rank of switches, that is, switches in the column representing the bank of 1A Igateselecting relays. The same sort of branchin-g yoccurs from the contacts SAI-2, that is, 8A1-2 branches olf into 4A1-3 and 4A2-1, which in turn branch oil into a column 2 group of gate-selecting relay contacts which in turn 'branches oif into a column 1 of the l bank gate selecting relays.

Thus, the A tree of circuits is branched olf yfrom the contacts 16A1-1 and the B tree of circuits is branched Voil` from the contacts 16B-1; the B tree branching in the same manner as the A tree.

Gates controlled in two groups occupying dz'jerent sections of the trackway As explained above, the gates which determine the locations at which various articles are discharged from the trackway are controlled in two different groups which occupy diierent linear sections of the trackway, that is, the first group of gates designated by the letter F are located in the forward sec-tion of the trackway, and the second group of gates designated by the letter R are located in the rear section of the trackway.

In the embodiment described herein the gates in the two sections do not occur in the same sequence in which the gate solenoids are numbered in FIG. 3. For .eX- ample, the gates in the F group arel controlled by solenoids 1 to 4, 12, 13, 14, 22,23 and 24, While the gates in the R group are controlled by solenoids 5 to 11, to 21, and 25 to 30.

Also, the gates are not all located within the trackway proper, but .some gates are located below the trackway, in the manner shown in copending application Ser. No. 109,427, now Patent No. 3,201,114 to .control entrances to two bins. Thus, the gates which are incorporated in the -trackway proper are Nos. 1, 22, 2, 23, 3, 24, 4, 25, 5, 26, 6, 27, 7, 28, 8, 29, 9, 30, 10, 31, and the lower gates are those having solenoids provided with double windings as shown in FIG. 3 and are numbered 11 to 21 respectively.

It should be noted that certain gates in the top row control a common entrance to two bins, and gates in the lower row select between the two bins. This requires the upper gate to be operated simultaneously with the lower gate to effect feeding into certain of the bins. This is accomplished by arranging normally open contacts on certain gate solenoids to effect operation of other solenoids when they are operated. For example, solenoids 12, 13 and 14 are provided with normally open contacts 12a, 13a and 14a which are connected to effect energization of solenoids 22, 23 and 24 simultaneously with solenoids 12, 13 and 14. Also, solenoids 15 to 21 are provided with normally open contacts 15a, 16a, 17a, 18a, 19a, 20a and 21a which effect operation of solenoids to 31 upon energization of solenoids 15 to 21.

Also, solenoids 3, 4, 11, 24 and 31 are provided with normally open, self-'holding contacts 3a, 4a, 11a, 24a and 31a.

Operation of switching system When a signal is received and stored on either the A store or the B store, the respective contacts in FIG. 3 will be operated depending on those code areas which reflected light during scanning causing the operation of their respective switches, FIG. 1, and thereby operated the appropriate numbered banks of gate selecting relays, A or B.

It will `also be noted that the AR relays, FIG. 2, have switch contacts in the AR column of FIG. 3. The AR relays, FIG. 2, are energized at the same time the B store receives a signal from the scanning devices.

The switch contacts in column AR, FIG. 3, are so set that if a signal received by the gate selecting relays in either store indicates that the article carrying that signal is to be deposited in a bin in the forward end of the sorter trackway, that signal will immediately be routed -by the selected tree circuit through the AR contacts to effect immediate operation of the appropriate F gate solenoid to open the corresponding gate.

As previously stated, the stored signal will be held stored .for two feed cycles, even though the signal has already been used. There is one exception to this statement which will be described shortly.

If, on the other hand, the received signal in the store is for -a gate and bin in the rear section of the sorter, then that signal will be stored for one feed cycle and then will be read out during the second feed cycle at which time the switch contacts for the AR bank relays will Ihave reversed due to the operation of either switch C7a or CSa, FIG. l, as previously described.

An example of the foregoing operation for FIG. 3 would be as follows:

Assuming that the A stores have received a signal from the scanner indicating an article bearing the coded designation for gate 2, this code would cause the operation of the relays 1, 4, 8 and 16 in the A group. Thus, a signal will be traced through the normally opened but now closed contacts 16A1-1, through the normally open but now closed contacts of relay 8A1-1, through the normally open but now closed contacts 4A1-1, through the normally closed side of contacts 2A11 and up through the normally open but now closed contacts lof 1A1-2 through the deenergized and normally closed contacts ARI-2 -to gate solenoid 2 and then to the other side of the D C. bus, thereby causing the energization of gate solenoid 2, FIG. 3, and the immediate opening of this gate. Even though this gate has been immediately raised, the signal will be stored and held in the A bank relays, FIG. 2, until switch CSa is operated by cam C8, FIG. 1. Upon the next closing of switch. C251, FIG. 1, the B bank of relays will receive the signal and the AR bank will energize; thus, the contacts ARI-2 will reverse, deenergizing gate solenoid 2 and allowing the gate to close. The ARI-2 contacts will stay in this reversed position for one more feed cycle, whereupon the AR bank of relays will deenergize and the AR1-2 contacts will revert to the position shown.

Assuming that the signal received on the B stores at the time that the AR relays were energized, and solenoid 2 was deenergized, was for a gate in the rear section of the trackway, such as gate 20, the following sequence of operation would then occur:

Stores 1B, 2B, and 8B would be energized, thereby reversing their contacts in FIG. 3, a circuit would be completed through the normally closed contacts 16B1-1, through the normally open but now closed contacts 8B12 through the normally open but now closed contacts 2B2-3 and through the normally open but now closed contacts 1B4-2 up to the contacts AR7-2. However, these contacts AR7-2 are reversed from those shown in FIG. 3 in that during this interval when the signal is rst received on the B stores, the AR relays were activated, thus, these contacts changed position. One feed cycle after the signal has been received by the B stores, the AR relays will be deenergized as previously described, and the contacts AR72 will revert to their normally closed position as shown in FIG. 3, and thus a circuit will be completed through gate solenoid 20 to the other side of the D.C. bus thus energizing the solenoid 20 and opening the gate. It will be noted that the signal is stored in the B relays for one complete feed cycle, before the contacts AR7-2 are reversed allowing the energization of solenoid 20. Upon the completion of a third feed cycle, the AR relays will again be energized and AR7-2 will reverse, thus deenergizing solenoid 20 and causing the gate to close.

The operation of cams C2, C7 and C8 has been previously described. With reference to FIG. l, the operation of the cams C1, C3, C4, C5 and C6 will now be described. p

Cams C1, C3, C4, C5 and C6 along with cam C2 all make two complete revolutions within the time it takes an article to go from the point where it is picked up or that is when clutch ORC is engaged for feed purposes until the letter travels off the end of the trackway. Thus, the feed cam C1, FIG. l, operates twice during this interval of time and thus feeds two letters to the trackway during the interval of time it would take one letter to travel the entire distance of the trackway.

Cam C3, FIG. 1, is an early closing cam for the first gates located in the rear section of the trackway, gates 5, 15, 16, 25 and 26. The article passes through these gates almost as soon as they are open. Thus, in order to insure that these gates have ample closing time, the switch C3a, FIGS. l and 3, is opened approximately 72 degrees of cam rotation, as shown in FIG. 4, prior to the operation of switches C7a or CSa which operate approximately 318 degrees after the initiation of one complete feed cycle.

Cams C4 and C5 are delay cams used for special purposes with respect to the opening of gates 4 and 31 where these gates are, respectively, the rearmost gate in the F section of the trackway and the rearmost gate in the R section of the trackway. Cam C4, FIG. 1, operates on switch C4a, FIG. 3, to delay opening of this gate upon the reception of a new signal from a new article, since at that time the prior article is approximately over this gate when the new signal is received. This delay is effective for approximately degrees of cam rotation as shown in FIG. 4 and allows gate 4 to open just after the feed cycle has started, which gives ample time for the article utilizing the old signal to clear the gate before the gate opens.

Cam C5, FIG. 1, operates switch CSa, FIG. 3, for an interval of about 8O degrees of rotation of the cam, FIG. 4, to prevent the false energization of gate solenoid 31 during a canceling operation. The switch C5a is closed long before the end of the feed cycle; thus, if the input signal is for gate 31, there is ample time for the euer- 9 gization of the solenoid in the event that the signal is for this gate.

Cam C6, FIG. 1, is utilized in conjunction with gates 3, 4, 14 and 24 and gates 11, 21 and 31 which are reof rotation of the cams C7 and C8 shown where these latter cams operate switches C7a and C8a. However, since these gates 3, 4, 14 and 24 are located in the rearmost portion of the forward section of 4the trackway, a full 180 degrees of revolution of either cam C7 or C8 is required to deliver the article to the bins represented by these gatesyin a like manner since gates 11, 21 and 31 `are located in the rearmos-t portion of the horizontal trackway, 360 degrees of rotation of either cam C7 or cam C8 is required to deliver the article to these gates. The gates just mentioned are provided with holding circuits already described and are held open upon energization of the solenoids. Thus, normal cancelation does not deenergize the solenoids of these particular gates and they remain energized through their holding circuits. These solenoids 3, 4, 11, 14, 21, 24 and 31 are all wired in common to the switch C611, FIG. 3, on the T2 bus side, and thus the cam switch contacts C6a keep the holding circuits closed for about 50 degrees of rotation of the cam C6 after the operation of the normal cancelation by either C7a or CSa.

Summary of operation Assuming that no letters or 'articles are traveling on the trackway and assuming that both storage banks A and B, FIG. 2, are empty and are not storing a signal, and assuming that cam C2, FIG. l, has closed switch C2a land assuming further that the code on the rst article to be scanned indicates the numeral 21, then the operation of my device will be as follows:

Code areas 16, 4 and 1 will be black; therefore, relays S1, S4 and S16 will not be energized. Light will be reflected into photoelectric cells 2 and 8 and therefore their relays SR2 and SRS will be activated thus causing current to ilow in switch coils S2 land S8, thus closing contacts S2a and SSa in FIG. 2. Assuming that the AR11-2 through AR12-3 contacts are in the position shown in FIG. 2, that is, the AR relays are deenergized, then a signal will be stored in the gate selecting relay 2A and 8A. Their respective holding circuits closed by contacts 2A3-3 and BA1-3 will ybe completed through contacts C8a.

At Vapproximately 30 degrees of cam rotation, starting from the point of clutch engagement, cam C1 will be activating its respective pickup switch and the letter or article which was just scanned will be fed into the trackway of the sorter. During this period, contacts 2a and 8a in FIG. 3 have all reversed due to the energization of the storage relays 2a and 8a. Thus, a circuit will be completed in FIG. 3 as follows: From the T1 bus side through the normally closed contacts 16A1-1 up through the normally opened but now closed contacts 8A1-2 down through the normally closed contacts 4A1-3, up through the normally opened but now closed contacts 2A2-3 and down through the normally closed contacts 1A4-2 and then to the normally opened side of contacts AR7-3.

It will be noted at this point that the contacts AR7-3 will not reverse until the AR bank of relays is energized, and this will not occur until cam C7 activates switch C7a, FIG. 2. This Aactivation will occur at 138 degrees of revolution of the particular cam or at 318 degrees after the initiation of the feed cycle. At this point, the AR relays will be energized and the contacts AR7-3 will be reversed, thus a circuit will be completed through the upper side of AR7-3, through gate solenoid 21, through the normally closed switch C6a and the gate 21 will open.

This signal for gate 21 was stored for one cycle of operation, that is, during the period the varticle was traveling down the forward section of the trackway. The gate did not open until the article had passed the mid-section of the trackway and was proceeding down the rear portion of the track.

When gate 21 is energized, a holding circuit through the contacts 21a carried by the gate solenoid 21 is completed to solenoid 31 which in turn closes contacts 31a to complete a holding circuit for solenoids 21 and 31 from the T1 bus side through to the T2 bus. Itvwill be re- -membered that these holding circuits were unique to those gates located in the rearmost portions of each section of the trackway. If any other gate had been selected other than these unique gates, a holding circuit would not have been necessary.

Energization of gate 31 was necessary in that I have described my control circuits -as being employed in a machine using a two-level arrangement of gates; obviously,`

if all the gates were arranged at the same level, then the energization of gate 31 solenoid would be unnecessary.

Gate solenoids 21 and 31 will not be deenergized until switch C6a, IFIG. 3, is opened by cam C6, FIG. 1, which will occur approximately 400 degrees of rotation of cam C6, after the gate was open.

At the time gate 21 was operated, switch C2a, FIG. 1, had closed again, the AR relays were energized thus reversing the positions of contacts AR11-3 through ARH- 3, and preparing the B bank of stores to receive the coded signal from the second article to be sorted. Assuming this article to be coded for bin 2, then photoelectric cells PE1, PE4, PES, PE1-6 will activate their respective relays which in turn will close the contacts Sla, 84a, SSa and S1611.

The circuit in FIG. 3 will now be completed through the normally opened but now closed switch contact 16B1, up through the normally open but now closed contacts SE1-1, up through the normally open but now closed contacts 4B1-1, down through the normally closed contacts 2B1-1, up through the normally open but now closed contacts IBI-2, through the normally open but now closed contacts AR1-2, which were activated upon the energization of the AR relays, FIG. 2, and then through gate solenoid 2 to the opposite bus; thus, solenoid 2 is energizedand gate 2 will open to receive the second letter.

This circuit will be opened upon the deactivation of i the AR relays which will occur when cam C8 trips or opens switch C8a,FIG. `2, after one more feed cycle.

The above description assumed that an article to be sorted was fed into the bin controlled by gate 2 during the rst cycle of storage for the B st-ores at about the same time that an article was fed into the bin controlled by gate 21, during the second cycle of operation for the A stores. That is, both articles were fed at approximately the same time. It will be obvious that with this arrange- 4ment, the signal received from the scanner by either store is utilized in either the rst or second feed cycle depending on whether the article carrying the code is destined for either the F or R sections of the trackway. In either event, the signal is stored for two feed cycles.

In the event that an .article carries no code (all blocks white), lthen obviously all of the stores in the group of storage relays prepared to receive Va signal will be activated and will reverse their switch contacts in FIG. 3. These contacts will not complete a circuit to any gate solenoid; thus for this period of no signal, no gate will operate for this storage unit. The article bearing no code marking will proceed down the trackwayl and off the far end where it can be received in an article-reject receptacle.

What is claimed is:

1. A control system for selectively operating gates in a document sorting machine, said gates being distributed along a trackway and each provided with an operating solenoid, said system comprising rst storage means for storing signals representing any gate in the trackway, second storage means capable of storing signals representing any gate in the trackway, input means supplying signals individual to different gates along the trackway in repeated cycles, means for alternately storing successive signals in said first and second storage means, each said storage means being effective to retain the stored signal throughout two signal supply cycles, and switching means alternately connecting the outputs of said rst and second storage means to a first group of solenoids controlling a group of gates in the forward section of said trackway and to a second set of solenoids controlling the group of gates in the rear section of said trackway.

2. A control system for selectively operating gates in a document sorting machine, said gates being distributed along a trackway and each provided with an operating solenoid, said system comprising first storage means for storing signals representing any gate in the trackway, second storage means capable of storing signals representing any gate in the trackway, input means supplying signals individual to different gates along the trackwey in repeated cycles, means for alternately storing successive signals in -said first and second storage means, each said storage means being effective to retain the stored signal throughout two signal supply cycles, and switching means operative during one signal supply cycle to connect the output of one storage means to the solenoids of gates in a forward end section of the said trackway and the outputs of the second storage means to the solenoids of the gates in the rear portion of the trackway, said switching means being operative in the next succeeding signal supply cycle to reverse the output connections of said two storage means whereby the output of said one storage means controls the solenoids of the rear section of gates and the output of said second storage means controls the solenoids of the forward section of gates.

3. In an article-sorting machine for sorting articles carrying a destination code which may vary from article to article, and in which the articles are conveyed in succession along a trackway provided with a number of discharge gates for effecting removal of articles from the trackway at locations spaced along the length of the trackway, the combination of code sensing means located to sense the code on the articles as they are supplied to said trackway, first storage means for storing a rst signal received from said sensing means, second storage means for storing a second signal received from said sensing means, switching means connecting said sensing means alternately to said first and second storage means,

12 means actuated lby said first storage means to apply said first stored signal to gate-operating means in one section of said trackway, and means actuated by said second storage means to apply said second stored signal to gateoperating means in another section of said trackway.

4. In an article-sorting machine, the combination according to claim 3 in which each signal storage means retains signals stored therein for a time interval in which two articles are supplied to said trackway, and including means operating in timed relation with the movement of articles along said trackway for alternately canceling the signals from said first and second storage means at the end of each two-cycle storage period.

5. A control system for an article-sorting machine in which each article carries a multi-digit code which indicates the destination for each article, said system comprising for each possible digit of the code, means to sense the digit if present and to effect storage of a signal in a store when a digit is sensed, a single-pole, doublethrow switching relay controlled by each signal store, said switching relays being connected in different ranks of a tree-switching system, and a plurality of gate solenoids connected to the branches of said tree-switching system whereby diterent combinations of said multi-digit code effects connection to dilerent ones of said gate solenoids.

6. A control system according to claim 5 and including a second set of stores, one for each digit-sensing means, and means for alternately connecting the digitsensing means for each digit from one store to the other in succession, a single-pole, double-throw relay switch controlled by each store of said second set and being connected in different ranks of a second tree-switching system, a second plurality of gate-operating solenoids, a single-pole, double-throw switch for each solenoid, and means to operate said solenoid switches to effect alternate connection of each solenoid lirst to a `branch of one treesystem and then to a branch of the second tree-system.

References Cited by the Examiner UNITED STATES PATENTS 2,707,569 5/1955 Benson 214-11 3,136,423 6/1964 Delplace et al. 214-11 X 3,176,839 4/1965 WhiteCar 209--74 r M. HENSON WOOD, JR., Primary Examiner.

C. SPADERNA, Assistant Examiner. 

3. IN AN ARTICLE-SORTING MACHINE FOR SORTING ARTICLES CARRING A DESTINATION CODE WHICH MAY VARY FROM ARTICLE TO ARTICLE, AND IN WHICH THE ARTICLES ARE CONVEYED IN SUCCESSION ALONG THE TRACKWAY PROVIDED WITH A NUMBER OF DISCHARGE GATES OF EFFECTING REMOVAL OF ARTICLES FROM THE TRACKWAY AT LOCATIONS SPACED ALONG THE LENGTH OF THE TRACKWAY, THE COMBINATION OF CODE SENSING MEANS LOCATED TO SENSE THE CODE ON THE ARTICLES AS THEY ARE SUPPLIED TO SAID TRACKWAY, FIRST STORAGE MEANS FOR STORING A FIRST SIGNAL RECEIVED FROM SAID SENSING MEANS, SECOND STORAGE MEANS FOR STORING A SECOND SIGNAL RECEIVED FROM SAID SENSING MEANS, SWITCHING MEANS CONNECTING SAID SENSING MEANS ALTERNATELY TO SAID FIRST AND SECOND STORAGE MEANS MEANS ACTUATED BY SAID FIRST STORAGE MEANS TO APPLY SAID FIRST STORED SIGNAL TO GATE-OPERATING MEANS IN ONE SECTION OF SAID TRACKWAY, AND MEANS ACTUATED BY SAID SECOND STORAGE MEANS TO APPLY SAID SECOND STORED SIGNAL TO GATEOPERATING MEANS IN ANOTHER SECTION OF SAID TRACKWAY. 